Let-off means for textile machine



May 14, 1957 G. E. CLENTIMACK 2,792,023

r LET-OFF MEANS FOR TEXTILE MACHINE Filed June 22, 1955 4 Sheets-Sheet 1 IN VEN TOR. Gzol'aes ECLENTIMACK Z KAZWz Z A TTORNE Y May 14, 1957 G. E. CLENTIMACK LET-OFF MEANS FOR TEXTILE MACHINE 4Shee ts-Sheet 2 Filed June 22, 1955 INVEN TOR. GEORGE E.CLENT|MACK A TTORNE Y LET-OFF MEANS FOR TEXTILE MACHINE Filed June 22, 1955 4 Sheets-Sheet 3 "5% r v I E' ZI'II HI 100 12s 4 M 2. I r W I Win 0 m minim:

' llil-lllllll 85 I i l I .32?

INVENTOR. GEORGE E. CLENTlMACK A TTORNE Y I May 14, 1957 Filed June 22, 1955 G. E. CLENTIMACK LET-OFF MEANS FOR TEXTILE MACHINE 4 Sheets-Sheet 4 IN V EN TOR. GEORGE ECLENTIMACK A TTORNEY LET-OFF MEANS FQR TEXTELE MACHENE George E. Clentimack, North Attlehoro, Mass, assignor to Draper Corporation, Hopedale, Mass, a corporation of Maine Application June 22, 1955, Serial No. 517,293

11 Claims. (Cl. 139-110) This invention pertains to means for letting off warp or other threads from beams or the like in textile machines, and particularly to control of the let-off means and function so as to deliver the warp threads uniformly under a prescribed condition.

It is a general object of the invention to devise a control means for a textile machine let-off which shall be very sensitive and adapted to compensate for variations in the tension of warp or other threads being let oif thereby to maintain a very uniform condition in the material being advanced.

A further object is that of providing control for a letoff means which shall sensitively and promptly adjust for all changes in tension which tend to be permanent, but which will merely absorb without aifecting the let-off means, all periodic variations which tend to be recurrent, but non-permanent.

A more specific object is that of devising a let-otf control which shall function to control a variable speed means through a resilient linkage coupled to a member having relatively high inertia and thus a resistance to change in operating condition of parts for relatively short periods of time only.

Other objects will be apparent from the following more detailed disclosure.

In various types of textile machinery such as knitting machines, looms and the like, warp or similar threads wound on a beam or beams are fed or let off at a rate dependent upon that at which they are required to be advanced for purposes of forming a fabric as they are combined or interlaced with other threads. Usually these beams are advanced by a let-oif or drive means the speed of which must be varied to compensate for decrease in diameter of the supply on the beam and also for maintaining a uniform tension condition 'in the threads.

Various devices have been used and these function well in many instances, although it is still desirable to let off such material under still greater uniformity and within closer limits as to tension conditions. As the diameter of the beam varies, compensation must be effective to speed up beam rotation so that linear speed of the material and tension shall vary as little as is practically possible. Along with this function, most fabric forming machines operate according to a cycle within which the warp threads are non-uniformly incorporated into a fabric, that is, tend to be demanded more rapidly at one part of the cycle than another and thus set up periodic variations in tension. Since most control is taken from tension bars, whip rolls or the like which bear upon the warp threads at some point between the beam and fabric forming instruments, these variations are imparted to the control means along with other changes in condition which are or would be permanent if not compensated. Reference will be made herein to periodic variation and to changes of permanent nature. 7

According to the invention, means is provided to conend of which a gear 28 is meshed with 2,792,023 Patented May 14, 1957 trol a variable speed drive means and comprises a linkage between a tension bar, whip roll or other thread tension sensing means, and a variable speed means for conveying indications from the first to the second means. This linkage has as a part thereof a member presenting considerable resistance to rapid displacement due to its inertia and other means functioning on that one which is resilient and which offers little or no frictional resistance to its movement.

According to one form of the invention, a variable speed means is controlled by ratcheting means continuously in operation, but permitted to affect the position of the variable speed mechanism as governed by a movable shield. This shield may be moved by means responsive to warp tension, but due to the presence in the linkage of an inertia and resilient members as above indicated, the shield or equivalent means actually permits only changes in ratio of the variable speed means as required to maintain as uniform as possible the delivery of the material while resisting changes due to periodic and cyclic variations.

The invention will be described by reference to specific embodiments thereof as illustrated in the accompanying figures of drawing, wherein:

Fig. 1 is a side elevation of a loom to which the in vcntion has been applied.

Fig. 2 is a similar view of a warp knitting machine.

Fig. 3 is a vertical section through a let-off means to which the invention applies.

Fig. 4 is a section taken at line 44, Fig. 3.

Fig. 5 is a section at line 5-5, Fig. 3.

Fig. 6 is a plan view of the unit, a part of the output side being shown in section.

Figs. 7 and 8 are elevations of a resilient arm and co operating parts which form a part of the control linkage. Figs. 9 and 10 are similar views of a modification.

Now referring to Fig. l, a loom to which the invention has been applied comprises, among other parts, a loomside 20, crankshaft 21 and camshaft 22. At the back of the loom a beam 23 is supported in bearings 24 in a conventional manner and has wound thereon a plurality of warp threads W which pass through the usual warp stop motion, harnesses and are interlaced with weft or filling threads to form a fabric. These latter parts and functions are not illustrated since they are so Well known.

The warp beam has ailixed at one side a gear 25 meshing with a pinion 26 fixed on shaft 27 at the other and driven by a pinion 29, Fig. 6 also. This latter pinion is keyed to the output shaft of a let-oft drive means to be described, but indicated here in Fig. l by numeral 30.

This drive unit has at its input side a sprocket 3i keyed to shaft 32 and a chain 33 is adapted to transmit power to the unit from any convenient rotating part of the loom. Here such drive is taken from the crankshaft 21 to which is fixed a sprocket 34. A tension sprocket 35 serves to keep the chain taut.

As the Warp threads W are drawn oif the beam, they are passed about a whip roll 36 or other tension responsive means. Here roll as is rotatable in arms 37 pivoted at 33 in a bracket carried by extensions 39 of the loomsides. A depending arm 49 at one side only is fastened to the arm pivot 38 and at its free end hinges at &1 to rod 42. This rod is guided in bracket 43 and a spring 44 under compression between the bracket and an adjustable collar 5$ forces arms 37 and roll 36 against the warp sheet as it is drawn over the roll. By adjustment of collar 45 the relative position of the roll and tension in the warp may be initially set for some desired value.

This whip roll functions in a known manner under influence of the warp and its positional variations are transmitted to the let-off unit 30 by novel means. control unit generally indicated by numeral 46 to be described in detail later, is governed through an inertia member 47 in turn connected by link 43 to arm 49 on shaft 50. Another arm 51 also fixed to shaft 50 is connected by link 52 to the free end of resilient arm 53 attached by adjusting holder 54 to pivot 38 for the whip roll mechanism.

Referring to Fig. 2, a warp knitting machine having more or less the usual construction includes a frame 55, Warp beam brackets 56, and warp threads drawn from beams 57 and 58. These warp threads are passed over tension bars 59 and 60 on arms 61 and 62 pivoted at 63 and 64 on brackets 65 and spring urged in an upward or clockwise direction to maintain tension on the threads as they are fed to needles at a knitting point at 66.

Both beams are driven to let off warp material by units 67 and 68 similar to unit 30, Fig. 1. These are controlled from the tension bars by linkage including resilient arms 69 and 70 and links 71 and 72. These arms are similar to the arm 53, Fig. 1.

While two textile machines which may employ to advantage the let-off and control means are herein described and claimed, these are given by way of example only and the invention applies to all such machines or others in which similar problems of warp thread feeding may be found.

Now referring to Figs. 3-6, the let-off unit-s are preferably of a reduction gear type in which between an input side and an output side there is a speed change mechanism. Power is taken in at the shaft 32 carried in bearings 73 and 74 in acasing 75 and its cover 76. This shaft carries a disk 77 which is free to slide within limits on the shaft but keyed to rotate with it. This is frictionally engaged between two disks 78 and 79 rotatable on a shaft 80 which is borne in arms 81 and 82, Figs. 3 and 4. These disks 78 and 79 are tapered as shown and are free to tilt slightly as they are pressed together into contact with disk 77 and another disk 83 which is the output or driven disk. Spring 84 affords the lateral pressure needed to keep the surfaces in contact so as to provide frictional driving force.

Driven disk 83 is keyed to shaft 85 as was disk 77 to shaft 32. That shaft is rotatable in bearings 86 and 87 and has fixed for rotation with it a worm 88 meshing with worm wheel 89. The latter is axially restrained but freely rotatable on hollow shaft 90 and rotates that shaft through a dog clutch, the lower part 91 of which is fixed to the worm wheel and the upper part 92, a collar, rides on the shaft 90 driving it through a pin 93 driven through the collar and passing through a slot 94 in the shaft.

Normally the clutch is engaged and as shaft 90 is turned, a Worm 95 keyed to it drives through the worm wheel 96 an output shaft 97, Fig. 6, to which is fixed the pinion 29 or other means by which the driving force of the unit is transmitted to the beam or other means upon which the warp threads are wound.

This shaft 97 is supported in bearings 98 and 99 mounted in an extension 100 bolted or otherwise attached to the casing.

Thus the power put into shaft 32 is transmitted through disks 77, 78, 79 and 83 to the double worm drive reduction and to the output shaft 97. In the event a manual adjustment or turning of the output shaft by hand is desired, the dog clutch may be disengaged by raising wheel 101 and knob 102 fixed to an internal shaft 103 which extends down within the hollow shaft 90 and through which pin 93 is also passed. When the hand Wheel is raised it elevates shaft 193 and by pin 93 disengages clutch element 92, but as the hand wheel is turned it will rotate shaft 103, clutch part 92 and shaft 91 since the parts are all forced to rotate as a unit by pin 93. However, shaft 90 merely turns in the worm wheel 89 and lower clutch 91.

The drive ratio is varied by moving the disks 78 and 79 toward or from the disks 77 and 83 and that is accomplished by swinging the arms 81 and 82 which actually constitute parts of a bell crank system. These arms depend from a hub 104 pivoted on an extension 185 of shaft 97. Two horizontal arms 106 and 107 have forked ends which take pins 108 and 189 extending from nut 110. This nut is threaded onto screw 111 cut on a shaft or spindle 112 borne at bushing 113 in the top of the casing and in a bearing in boss 114 at the side. Collars 115 and 116 resist axial thrust of the shaft while the latter and another 117 limit possible travel of nut 110 along the screw.

This shaft and nut 110 serve to maintain a set position of the disks 78 and 79 and to swing them to positions Where they are engaged by disks 77 and 83 farther from or closer to their peripheries so that the ratio of the drive is stepped up or down as required. That is accomplished through ratchet wheels 118 and 119 fixed to shaft 112 above the casing, one having teeth adapted to be ratcheted clockwise and the other counterclockwise. Pawls 120 and 121 are pivoted at 122 on arm 123 of a lever which is also swung about the shaft as a center. The other arm 124 of this lever is connected at 125 to link 126 of an eccentric sheave 127. The latter is actuated by eccentric 128 which rotates with shaft 90 so that the arm 123 and pawls carried thereby oscillate to and fro and, depending upon control by a shield 129, will rack the shaft 112 either to the right or left.

Pawls 120 and 121 are spring pressed to engage their respective ratchet wheels and may be prevented from doing so as the shield is moved under one or both. This shield is fixed to the relatively heavy, solid drum 47 freely rotatable at the upper end of shaft 112, preferably on antifriction bearings. This drum is heavy enough so its inertia serves a useful function in control of the device as will be explained.

The position of the drum is under control of a system including a link 48 connected to it at 130 and to the end 131 of arm 49 attached to spindle 50 carried in bearings 132 and 133 in bracket 134 attached at the side of the casing, Figs. 1, 3, 4 and 6. Movement is transmitted from control means responsive to condition of the threads being advanced through means including a link such as the link 52 attached to an arm 49 suitably secured to spindle 50.

In the showing the parts are in substantially a neutral position. A graduated scale 135 and indicator bar 136 serve for initially setting or centering the device. Two stops 137 and 138 are effective against the bar to limit the swing of the drum and shield.

A click or other stop 139 engages the teeth of one or the other of the ratchet wheels to hold the shaft 112 against unintended displacement.

Now referring to Figs. 1, 7 and 8, a resilient arm includes the flat spring 53 one end of which is clamped against a fiat side of a split hub 140 which is in turn clamped on the end of whip roll pivot 38. A plate 141 drawn into place by screws 142 serves the first mentioned function while the hub is held in place by screws 143.

At the free end a connection for link 52 comprises a slotted member 144 clamped to the end of the strip and drilled and tapped to receive a short pivot stud 145.

Spherical link connections have been shown as used throughout and that is preferred since it is desired to keep the friction as low as possible and alignment problems are thus simplified.

To take care of final and very precise settings, a screw 146 with a serrated head 147 is threaded through an extension 148 to the hub 140 and may be used to bias the spring strip against its load in one direction. A ball 149 spring loaded as shown engages the serrations and maintains the setting. a

In Figs. 9 and 10 a modification takes the form of a non-flexible arm 150 freely pivoted at the end of a shaft 38 and axially held between a clamped hub 151 and a collar 152. The hub 153 of the arm is preferably as freely borne as practicable and lubrication is provided at this point. Any suitable link may be attached at the free end of arm 150 to convey its motion to a unit such as that herein described.

In order to absorb periodic vibrations, an extension 153 bent laterally anchors a rod 154 threaded at its ends and having springs 155 and 156 compressed between stops on the rod and a lug 157 on the arm.

Both these arms will transmit a permanent change of position of the shaft 38 or 38 through a link to the speed control means, but will absorb periodic vibrations so long as at the other end of the linkage there is some means easily moved when the element of time is sufficient, but oifering considerable inertia to the periodic and relatively rapidly recurring vibrations.

While examples of ways in which the invention may be applied here relate to swinging or oscillating tension bars and the like, it is to be understood that the invention contemplates reciprocable motions of all sorts from which an indication of warp or other thread condition may be taken. The periodic vibrations or oscillations may be of differing frequencies and magnitudes, but in all instances these will recur at a much more rapid rate than will permanent variations in tension values. In looms these periodic vibrations occur at something like 200 times per minute as an average figure, although there are looms in which they recur less frequently and also much more often. In knitting machines periodic oscillations occur at greater frequencies, but are usually of lesser magnitude.

The requirement for permanent speed changes occur on one hand very slowly and infrequently by comparison. The gradual depletion of the material on the beam, of course, requires compensation by way of increased angular speed, but that takes place very slowly, and gradual tendencies for tension to increase or decrease are taken care of by a few ratcheting movements in one direction or the other, these being needed only every few minutes. The percentage variation in tension is kept at a low value.

To review the operation, assume the loom or knitting machine to be running, the tension bars oscillate and the beam or beams are driven by the units in which the disks will be intermeshed to that extent to give proper ratio for feeding the warp material as needed. The oscillation of the bar will merely flex spring strip 53 or springs 155 and 156 as the inertia of the drum 47 resists the forces transmitted through the linkage to it. There is little friction in this linkage and so long as oscillations tend to be equal at either side of a neutral plane through the resilient arm, inertia of the drum should be sufficient to resist movement or permit very little movement for that period of time during which the rapidly, periodically effective forces are brought to bear. However, when tension values increase or decrease appreciably, the periodic oscillations set up forces greater in one direction than the other taking the neutral plane as a reference point and slowly the drum is moved to a new position until equilibrium is established. If this change moves the shield sufficiently to uncover the ratchet wheel teeth, the appropriate pawl will rack the shaft 112 and move nut 110 to adjust the output ratio of the speed change unit to compensate for the tension difference responsible for the indication. As

modifications thereof falling within the spirit of the invention and the scope of the claims.

I claim:

1. In a textile machine the combination of cooperating devices for combining threads including warp threads for forming a fabric, means for letting off the said warp threads which includes as a part thereof a variable speed drive means, and control means responsive to change in condition of said warp threads for varying the output of said variable speed means which comprises a freely movable, rotary member offering relatively high inertia and other and interconnected means to vary the position of said rotary member which includes a mechanical linkage from said means responsive to change in condition of said warp threads to said rotary member having interposed therein a spring arm for conveying to the rotary member changes in warp condition which are of relatively permanent nature while absorbing periodic vibrations due to cyclical changes in the warp threads.

2. In a textile machine the combination of cooperating devices for combining threads including warp threads for forming a fabric, means for letting off the said warp threads which includes as a part thereof a variable speed drive means, and control means responsive to change in condition of said warp threads for varying the output of said variable speed means which comprises a means adapted to be ratcheted in either direction, pawls for so ratcheting said means and a drum having relatively high inertia and carrying a shield for preventing one or both pawls from affecting said means, and means for indicating changes in tension of said warp threads and linkage from said last mentioned means to said drum in which is included a resilient arm.

3. In a textile machine the combination of cooperating devices for combining threads including warp threads for forming a fabric, warp thread tension indicating means periodically movable with vibrations in said threads, means for letting off the said warp threads which includes a beam driving unit having therein a variable speed drive, control for the variable speed drive which includes a member and means to ratchet it in either direction, a shielding member for inhibiting said ratcheting function and a member having relatively high inertia movable with said shielding member, linkage from said tension indicating means to said member having high inertia including an arm resilient and flexible enough substantially to absorb periodic oscillations of the indicating means when resisted by said member having relatively high inertia.

4. In a textile machine the combination of cooperating devices for combining threads including warp threads for forming a fabric, warp thread tension indicating means periodically movable with vibrations in said threads, means for letting off the said Warp threads which includes a beam driving unit having therein a variable speed drive, control for the variable speed drive which includes a member and means to ratchet it in either direction, a shielding member for inhibiting said ratcheting function and a member having relatively high inertia movable with said shielding member, an arm fixed for movement with said thread tension indicating means, said arm having as a part thereof a spring strip relatively easily flexed through a considerable angle and a linkage interconnecting said arm and said member having relatively high inertia.

5. Mechanism as defined in claim 4 wherein said arm comprises a hub, a link connecting member and a thin resilient spring strip clamped to said hub at one end and carrying said member at its opposite end.

6. Mechanism as defined in claim 4 wherein said arm comprises a hub, a link connecting member and a thin resilient spring strip clamped to said hub at one end and carrying said member at its opposite end, and means for initially biasing said spring strip in one direction.

7. Mechanism as defined in claim 4 wherein said arm comprises a hub, an arm member freely pivoted on said hub, an extension to said hub and a boss intermediate the ends of said arm member and spring means carried by said extension and engaged against said boss, one at one side and one at the other side and under compression so that said hub and arm member are resiliently interconnected.

8. In a loom the combination of warp beam, a movable Whip roll over which waip threads are drawn from said beam and resilient means urging said whip roll against said warp threads, means for letting off said warp threads by rotating the beam which includes a unit having therein a variable speed drive, a control for the variable speed drive which includes a member and means to ratchet it in either direction, a shielding member for inhibiting said ratcheting function and a member having relatively high inertia movable with said shielding member, linkage from said whip roll to said member having high inertia including an arm resilient and flexible enough substantially to absorb periodic oscillations of the whip roll when resisted by said member having relatively high inertia.

9. Mechanism as defined in claim 8 wherein said member having high inertia comprises a drum to which is attached said shield and said arm comprises a hub and link connecting element attached at opposed ends of a spring strip.

10. In a knitting machine the combination of a warp beam, a tension bar bearing upon warp threads as they pass from said beam to a knitting point, and resilient means urging said tension bar against said warp threads, and means for letting off said warp threads by rotating the beam which includes a unit having therein a variable speed drive, control for the variable speed drive which includes a member and means to ratchet it in either direction, a shielding member for inhibiting said ratcheting function and a member having relatively high inertia movable with said shielding member, linkage from said tension bar to said member having high inertia including an arm resilient and flexible enough substantially to absorb periodic oscillations of the tension bar when resisted by said member having relatively high inertia.

11. Mechanism as defined in claim 10 wherein said member having high inertia comprises a drum to which is attached said shield and said arm comprises a hub and link connecting element attached at opposed ends of a spring strip.

References Cited in the file of this patent UNITED STATES PATENTS 1,729,130 Seymour et a1 Sept. 24, 1929 2,308,430 Bolden et al. Ian. 12, 1943 2,637,184 Schoenster May 5, 1953 2,664,724 Lambach et al. Jan. 5, 1954 

